1. Field
This invention relates to a process for dense packing of bags containing lightweight material on a pallet for handling and transport.
2. Prior Art
It is, of course, a common practice to load and secure items for transport onto a standard wood pallet and move those palletized items by conventional transport. Where such items have dimensions for exactly covering the pallet, an efficient space utilization is obviously obtained. Where, however, a particular item has such dimensions that it cannot be conveniently stacked with others to fully cover a standard pallet, stacking techniques that have been employed to provide a stable stack of such items have heretofore failed to obtain an efficient space utilization. The present invention, distinct therefrom, provides for both a stable stack and an efficient space utilization. Below are cited a number of patents that include apparatus similar to that preferred for practicing steps in the palletizing process of the present invention, none of which, however, anticipate the present process.
Patents by Cline, U.S. Pat. No. 3,566,326, and Place, et al., U.S. Pat. No. 4,220,431, show cage arrangements for providing side support to sacks, boxes, or the like that are stacked onto a pallet, which sides are then removable for allowing a forklift or the like to have access to the pallet for lifting and movement thereof. These support structures are similar to that preferred for use in a practice of the process of the present invention.
Examples of apparatus and techniques for palletizing standard-sized items are shown in patents by Miller, U.S. Pat. No. 2,813,638; Wolske, U.S. Pat. No. 3,961,459; and Miller, U.S. Pat. No. 3,164,080. These patents, additional to handling of uniform items that apparently have suitable dimensions to fit exactly on a pallet, also provide a wrapping procedure, similar to that preferably employed in a practice of the present invention, for maintaining the stack of items to that pallet during handling and transport. Additionally, a patent by Cordes, et al., U.S. Pat. No. 4,098,051, shows irregular articles contained within a shrink wrap that is like that employed in a practice of the present invention.
Another arrangement for maintaining a stack of items on a pallet is shown in a patent by Forsythe, U.S. Pat. No. 3,059,787, that involves application of an adhesive in the form of a tape, having adhesive layers on both sides, between bags to hold these bags together and maintain stack integrity. This arrangement also relates to bags that fit on a uniform-sized pallet and is not directed toward a stacking technique like that of the present invention.
Earlier stacking apparatus and procedures directed toward the stacking of bags not of a size to be conveniently arranged to fill or cover a pallet have generally involved an overlapping or layering arrangement that leaves unfilled spaces or openings on each layer. Distinct therefrom, the stacking procedure of the present invention provides a stack where all the space in each layer is filled. Some such earlier arrangements that do not anticipate the dense pack stacking procedure of the present invention are shown in patents by Cole, et al, U.S. Pat. No. 2,655,271; Slater, U.S. Pat. No. 2,675,928; and Beaty, Jr. et al., U.S. Pat. No. 3,730,357.
Certain of the cited art, as outlined above, utilizes apparatus like that preferred for a practice of the process of the present invention as, for example, the use of a cage structure for stacking of items on a standard wood pallet and the preferred shrink wrap techniques for maintaining stacked items. None, however, show the unique stacking procedure of the present invention for achieving a dense stacking of bags of lightweight, loose material that are not of a shape convenient for filling or covering a standard pallet. Preferably, the present invention provides a procedure for stacking of three-cubic-foot bags or sacks of lightweight, loose material, such as redwood bark, that has characteristics of flow within the bag suitable for filling in open areas between layers of such bags or sacks.